Turbo-machines such as compressors and turbines generally include a rotating assembly having a centrally located rotor shaft and a plurality of rows of rotating blades attached thereto, and a corresponding plurality of rows of stationary vanes connected to the casing of the turbo-machine and interposed between the rows of rotating blades. A working fluid such as air or combustion gas flows through the rows of rotating blades and stationary vanes to transfer energy between the working fluid and the turbo-machine.
A blade of a turbo-machine typically includes a root section attached to the rotor, a platform section connected to the root section, and an airfoil section connected to the platform section on a side opposite from the root section. Corresponding surfaces of platform sections of adjacent blades in a row of blades abut each other to form a portion of the boundary defining the flow path for the working fluid. While it would be desirable to have adjacent platforms abut in a perfect sealing relationship, the necessity to accommodate thermal growth and machining tolerances results in a small gap being maintained between adjacent platforms.
It is known that turbo-machines have incorporated various types of devices to address the need of sealing the gap between the platforms of adjacent blades. Generally, such devices are generally either expensive to manufacture, lack sufficient sealing effectiveness for modern combustion turbine applications or have geometries vulnerable to thermally-induced stress that can develop along the platform side and can lead to the formation of cracks.
Accordingly, it is desirable to provide an improved blade assembly for sealing a gap between the platforms of adjacent rotating blades in a turbo-machine. It is further desirable to provide a blade assembly for sealing that can be manufactured by relatively inexpensive manufacturing techniques, has a geometry that reduces concentration of stress and avoids crack formation, and provides a desired sealing effectiveness.